The BBC director general, Mark Thompson, has launched a robust counter-attack against critics of BBC radio's dominance of the medium in the UK, telling commercial broadcasters to look at their own "business strategies" rather than blame the corporation every time they lose share or revenue.

He said there was no evidence that the corporation was "crowding out" commercial competitors in radio, adding that they faced a bigger threat to the businesses from the internet than from the corporation.

"Don't assume that every time somebody gets into difficulty it is the BBC's fault. Some parts of commercial radio are doing very well. There is no evidence at all that the BBC is crowding out commercial activity," Mr Thompson told a Broadcasting Press Guild lunch today.

"The principal issue faced by commercial radio broadcasters are from internet advertising not the BBC. The battle is about where the advertising dollars go for these media and the BBC has nothing to do with this," he said.

Singling out Radio 3 and Radio 4 for special praise, he added: "[BBC radio] is a success story - I am not going to apologise for our success."

According to the most recent quarterly Rajar audience figures released in February, the BBC had its biggest-ever lead over its commercial radio rivals, with the gap in audience share now more of than 12 percentage points in the final quarter of 2005. BBC Radio had a 55.1% share of the total UK radio market, according to these figures.

However, Mr Thompson said that BBC radio is "exogenous" - a word referring to something which comes from outside a system - to the commercial market place.

He also defended the level of salaries paid to BBC radio presenters unveiled in a recent series of leaks.

These included claims that Radio 2 breakfast DJ Terry Wogan is paid £800,000 a year, while fellow Radio 2 presenter Jonathan Ross picks up £530,000 for one three-hour show a week.

Radio 1 DJ Chris Moyles is reported to take home £630,000 a year, while Sara Cox gets a £200,000 pay packet for two weekend shows.

Mr Thompson disputed the accuracy of "some of" the reported figures and said: "I don't think we have overpaid them and I have no apologies at all that we try and get the best talent for the BBC's licence-fee payers.

"The challenge [for commercial players] is around the fragmentation of the advertising-funded marketplace."

He added that commercial radio players must find a "creative strategy" which "must be sufficiently strong for the world of podcasting and so on".

Mr Thompson said that "they have got big issues but it is not the single issue of share", adding that Radio 1 and Radio 2 offered a service which was unavailable in commercial radio.

"If you look at the ratio between music and speech these stations are doing something that no other commercial radio station does," he added.

Mr Thompson's comments were dismissed as "arrant nonsense" by Paul Brown, the chief executive of the Commercial Radio Companies' Association.

"I am not surprised that he is saying this at a time when he is trying to secure more money for the BBC," Mr Brown said.

"But only a state-funded broadcaster could come out and say that the number of listeners you get has no relevance to the amount of advertising and advertising revenue you can get. It is arrant nonsense.

"Time and time again the BBC keeps moving away from its responsibility and if he gets his way then they will dominate every media available. It is a very dangerous thing for a state broadcaster to do."

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